LINEAMENTI MORFODINAMICI E SEDIMENTARI DEL LITORALE DEI CAMPI FLEGREI (CAMPANIA, ITALIA MERIDIONALE)

Abstract

Morphodynamical and sedimentary features of the coast of the Phlegrean Fields (Campania, Southern Italy). The Phlegrean Fields are
one of the most famous volcanic areas in the world. During the last 50,000 years this area has been formed by the activity of many
eruptive centres and today it has the typical morphology of a volcanic field. At present the Phlegrean Fields are active, even if the last
event was recorded a long time ago: the Monte Nuovo eruption in 1538. The endogenous activity is currently recorded by the frequent
inversions of the vertical crustal movements (bradyseism), by the sismicity connected to the bradyseismic events and by the intense
thermal activity. From the Roman Age up to this time the features of the bradyseismic events have not been defined yet because of the
type and complexity of the phenomena; recent research shows that the greatest submersion (17÷18 m) was verified during the early
Middle Ages. After the resurgence phase the ground has risen only 6÷7 m: the presence of the submerged Roman ruins shows the
extent of the sinking.The coastal area could be divided into three clearly diversified sectors: the shore of Cuma constituting the western boundary; the Gulf of Pozzuoli representing the eastern zone, more complex and articulate; the shore of Miliscola, the central connection between the two preceeding sectors.
The shore of Cuma.This sector, extending for about 6 km with N-S orientation between Licola Mare and Monte di Procida promontory,
constitutes the terminal part of the coastal plain of the Volturno River, which flows approximately 20 km to the NW. The low and sandy
beaches are limited inland from some foredune ridges, partly natural and partly urbanized. In the northern sector, behind the foredune ridges, there is a wide swampy area reclaimed during the last century ("Mazzoni area and Licola Lake") and in the southern sector there is the Fusaro coastal Lake. In the central part the promontory of Cuma interrupts the outline of the coast; this promontory was the centre of the Acropolis during the Greek-Roman Age, but today the Acropolis has almost entirely disappeared. Within the depth of 5 m the submarine beach shows one or two bar-trough systems: the inner one is crescentic and frequently connected to the rhythmic topography of the shoreline, while the outer one is linear and situated at a distance of about 100 m from the coast. A gentle slope characterizes the submarine beach beyond the bar-trough zone. The evolution of the shoreline presents a general erosional tendency during the years 1980-1987, whereas a tendency to the progradation is evident during the years 1987-1998. The prevailing wind sector is delimited by the 180°-330°N azimuth; most storms are come in from the 270°-300°N sector.
The shore of Miliscola.The shore of Miliscola is situated between the Monte di Procida and Capo Miseno promontories and has an
extension of approximately 2 km; it is limited inland from the Miseno coastal Lake. In the western tract we can find various defence
works, while in the eastern tract a wide beach is evident. The submarine beach is characterized by a small bar-trough system within the
3 m depth and within a distance of less than 75 m from the coast. Eight circular breakwaters have been built from 1980 to 1988 because of strong erosion during the middle '70ies; in these years these defence works have brought an evident beach restoration. After which, until 1996, the shoreline position behind the breakwaters has remained substantially unchanged, while in the eastern part of the sector (toward Capo Miseno) an erosional tendency was observed with a value of 0.5 m/y.
The Gulf of Pozzuoli.This sector, extending for over 9 km and forming two large semi-circular zones with an W-E orientation, shows
high and rocky coasts alternated with small, low sandy beaches. The prevailing wind sector is delimited by the 120°N and the 200°N
azimuth; the significant waves come by the 120°-130°N and 180°N azimuth; the maximum fetch and the greatest energetic potential
concerns the 180°N azimuth. In this area the modifications are very evident, natural as well as and anthropic. Among the natural ones
there are the bradyseismic events, that have caused the submersion of entire coastal tracts (for instance: the structures of the Portus
Iulius, the harbour of the ancient Roman imperial navy) and the Monte Nuovo eruption in 1538, that changed the coastal configuration
in the western zone of the Gulf. Among the anthropic ones there is a strong urbanization (“ILVA” iron and steel industry, various defence work, artificial coastal platforms) that has completely destroyed the natural environment of the area.